A transport network is typically composed of nodes at various locations that are interconnected by optical fibers, to transport traffic over long distances (such as distances between cities). The traffic includes discrete units of data e.g. conforming to Internet Protocol (IP), as well as time-sensitive streams of data as in voice circuits in traditional telephony. Each node in the transport network typically provides one or more functions for creating signals which are transmitted on the optical fibers.
FIG. 1 illustrates a prior art network which implemented using routers to process IP packets, using multiservice provisioning platforms (MSSPs) to generate optical signals, and using optical add drop multiplexers to transport the optical signals across the transport network. In the architecture illustrated in FIG. 1, a flow of packets from node A to node Z is typically processed at each intermediate node, I, J and K. An optical signal generated by node A may contain not only packets for node Z but also packets for intermediate nodes I, J and K. In addition to packet traffic, an optical signal from node A to node I may also contain time-division-multiplexed (TDM) traffic, such as SONET.
The inventors of the current patent application note several drawbacks in using a combination of routers, MSSPs that lack an optical backplane, and OADMs as shown in FIG. 1. Specifically, the current inventors believe that router-based transport is expensive, consumes precious resources, and compromises network performance due to higher latency. Moreover, the current inventors believe that MSSPs being based on SONET/SDH circuit-based hierarchy are obsolete because packet traffic over transport networks is increasing significantly relative to traditional telephony voice traffic. For example, increase in packet traffic is caused by residential users' demand for packet-based applications, such as transport of video over the Internet. As another example, increase in packet traffic is caused by business users expanding enterprise-wide Ethernet based networks to reach across the Internet. Accordingly, the inventors of the current patent application believe there is a need for improvement in network elements of a transport network.